The results obtained in this study provide an experimental verification of gas-liquid interface shifting within the membrane wall of both single-channel and multi-channel membrane contactors and its influence on the performance of catalytic three-phase membrane reactors. The primary objective was to demonstrate that it is possible to displace liquid occupying membrane pores and control the gas-liquid interface position within the membranes of different geometry by applying sufficient trans-membrane pressure difference. Liquid displacement from the membrane wall and consequent reduction of the diffusion path of the gaseous reactant enabled more efficient operation of membrane contactors. The second part of the investigations concerned mass transfer and reaction studies conducted at different operating conditions. Ascendance of the gas-liquid interface position on the effectiveness of the catalytic membrane reactor was studied by conducting catalytic liquid-phase nitrite hydrogenation. A catalytic membrane was prepared via metallic palladium depositions within the porous structure of tubular membrane using the incipient wetness impregnation technique. The performed experimental study established effects of various process parameters (such as diffusion path of the reactant, liquid phase re-circulation rate, use of a static mixer) on the overall performance of the membrane reactor.